Hitherto, there has been provided a system for determining a doze state, for preventing accidents caused by the doze and the like of a driver of automobiles or railway cars, a pilot of an air-craft or an operator of a flight control machine, from the tilt of head or the number of blinking times of the driver(for example, see patent reference #1 and #2).
In addition, there has been provided a system for sounding an alarm or for activating an automatic brake, by regarding as a doze if the duration of no-operation exceeds a predetermined period of time or a sensor placed in a specific location on an operating console is not touched for a predetermined period of time.
Patent Reference #1
JP-A-11-161798 (pp. 2-3, paragraphs 7 to 12; pp. 5, paragraphs 36 to 37)
Patent Reference #2
JP-A-9-109723 (pp. 5, paragraph 50)
In the system disclosed in such references as mentioned above, because the tilt of head or the number of blinking times to be determined has a considerable variation among individuals, the determination of doze is often entrusted to a subjective decision, resulting in a difficulty in making an accurate determination, and it has been impossible to distinguish a state immediately prior to doze from a sufficiently wakeful state, leading to a problem that it was not possible to completely accommodate the prevention of accidents.
In addition, because sensors or cameras are needed to be put on to or in the vicinity of the driver's body, there are disadvantages that the device needs a significant effort to be put on and taken off, that the installed device is a hindrance for driving or piloting and that the device is a distraction.
The system for sounding an alarm or operating an automatic brake if no operation is done for a predetermined period of time may misread that the driver is dozing although he or she is not, when the duration of no-operation has been accidentally prolonged, requiring the subject has to drive while always paying attention to do some operation posing a problem that the system tends to induce an accident on the contrary.
The setting of the period of time for the detection of doze is after all performed often based on a subjective decision; therefore an accurate determination of psychosomatic state was unlikely to be achieved.